Industrial applications involving mobile systems can benefit from the use of wireless technology. However, wireless communication has not been widely accepted on the factory floor due to its difficulty in achieving the timely and reliable transmission of messages over error-prone wireless channels. This paper presents an autonomous guided vehicle (AGV) path tracking wireless control system where an accurate delay estimation scheme is shown to be the key for successful operation. The control architecture consists on an AGV connected through a wireless network to a controller. To mitigate the negative effects that varying time delays in data transfer have in the networked control loop, the controller performs two tasks at each loop operation. First, it uses a Kalman filter to produce an optimal delay estimate considering a simple stochastic model of the wireless delay dynamics. Second, each delay estimate is employed to infer the real AGV position which permits to compute the appropriate control commands. Results show that the proposed technique provides more efficient and effective operation for path tracking control compared to similar previously proposed solutions.

Peer Reviewed